Obturating wad



June 6, 1961 H. E. CLARK, JR

OBTURATING WAD Filed Dec. 4, 1958 'rlllI-Ii FIG. 6

INVENTOR. HOMER E. CLARK, JR. QA K ATTORNEY sibility requisite for desired performance.

2,986,998 OBTURATING WAD Homer E. Clark, Jr., Alton, Ill., assignor to Alcan C0111! pany, Incorporated, Foster Township, 111., a corporation of Illinois Filed Dec. 4, 1958, Ser. No. 778,093

9 Claims. (Cl. 102-42) This invention relates in general to shotgun cartridges and, more particularly, to certain new and useful improvements in obturating wads therefor.

It is an object of the present invention to provide a shotgun cartridge wad for disposition between the propellant explosive and shot and being so designed as to pro vide an optimum gas seal with a gun barrel.

' It is a further object of the present invention to provide a gun Wad of molded plastic construction whichdoes not disintegrate under firing pressures or through the heat generated by the explosion of the charge so as to conduce to a symmetrical shot pattern. 1 i

It is a further object of the present invention to provide a gun Wad of the character stated fabricated of material which is compressible so as to cushion the initial explosive impact for exercising a damping action on transmission of the explosion to the shot mass.

- It is an additional object of the present invention to provide a gun wad having unique structural characteristics to allow the same to be placed in snug, superimposed relation upon the propellant charge so that no undesirable air pockets with attendant pressure are developed.

It is a still further object of the present invention to provide a gun wad which may be most economically constructed and which is reliable in usage.

These and other detailed objects are obtained by the structures illustrated in the accompanying drawing .(one sheet) inwhich- FIGURE 1 is a side view of a shotgun cartridge, a

ites g portion of the body wall being broken away, having an obturating wad constructed in accordance with and embodying the present invention. FIGURE 2 is a top plan view of the obturating wad illustrated in FIGURE 1.

* FIGURE 3 is a bottom plan view.

FIGURE 4 is a side view, with a portion in section. FIGURE 5 is a top plan view of another form of obturating wad constructed in accordance with and embodying the present invention.

5 FIGURE 6 isa vertical transverse section taken on the line 6-6 of FIGURE 5.

Referring now by reference characters to the drawings which illustrate practical embodiments of the present invention, A designates a shot shell or shotgun cartridge having a suitable base 1 and the usual tubular body 2 fabricated as of paper, metal, or the like. A primer assembly (not shown) is mounted in the base and thereabove, within body 2, is disposed a propellant charge 3.

Disposed in immediately overlying relationship to propellant charge 3 is an obturating wad 4, shown in detail in FIGURES 2, 3 and 4, confining said charge 3. Above wad 4 are superimposed conventional filler or separator wads 5, 6 fabricated of any suitable material, such as felt,-pulp, etc. Provided upwardly of said wads 5, 6

is the shot charge 7, preferably of multimissile character;

the upper end of shell A is closed in any customary manner, as, for example, by infolding of the body.

' Obturating wad 4 is of molded construction and fabricated of compressible, plastic material. It has been found that polyethylene is the preferred material of construction sinceit possesses the sturdiness, durability, and compres Said Wad 4 comprises a body of generally cylindrical configuration and opening into its upper end is a relatively deep, cen tral, annular recess 8, the base of which is the upper face of the base wall 9 of said wad. Said recess 8 includes a lower portion 8' defined by an inner, circular, side wall 10, upstanding from base wall 9, and an upper communicating portion 11 of increased diameter defined by an annular shoulder 12 presented at the upper end of side wall 10 and the inner face of the outer side wall 13 of wad 4. An upstanding hub or tubular portion 14 concentric with recess 8 extends upwardly from base wall 9 and having its upper end face planarwise parallel with the upper surface of outer side wall 13. Coaxial with hub 14 and projecting downwardly from the bottom face of wad 4 is a short extension 15, and extending through hub 14, base wall 9, and extension 15 is an axial bore 16, being of relatively small diameter, which may normally be in the order of 1 millimeter.

The bottom wall 9 of w'ad 4 is of circular configuration and planarwise perpendicular to the axis of bore 16, while outwardly of said bottom wall 9 there is provided a pcripheral flange 17, the inner face 18 of which is spaced outwardly of the outer face of inner wall 10, whereby the same together with a connecting top portion 19, forming the underface of shoulder 12, defines an annular recess 20 surrounding inner wall 10. Said flange inner face 18 tapers downwardly and outwardly toward its lower end so that the lower end portion thereof, being relatively thin, will constitute a zone 21 of relative flexibility. The outer face of flange 17 is coincidental with the outer wide wall 13 of gun wad 4. As shown in FIGURE 1, wad 4 is presented with respect to propellant charge or powder 3 so that bottom wall 9 is in immediate contact with said charge '3 with extension 15 projecting thereinto and being entirely surrounded thereby, and withsaid charge being received within recess 20.

Projecting radially from tubular portion 14, within recess 8, is a plurality of equally spaced ribs or spoke members 22 having lower and upper portions 23, 23, which latter at their outer end extremities are respectively integral with the inner face of inner side wall 10 and outer side wall 13*. Thus, ribs 22 connect the outer portions of wad 4 with its central portion so as to present an integrated,'sturdy, and rigid structure. It will be seen with reference to FIGURE 1 that annular recess 20"opens toward propellant charge 3 so that upon firing the gases of explosion will, on expanding, immediately exert an outward pressure upon flange 17 to force same into sealing engagement with the gun barrel, preventing gas leakage. The flexibility of the lower end portion of said flange 17 assures the substantially simultaneous de- 'velopment of a seal upon firing, as such thin edge portion will, requiring relatively less pressure, be brought into engagement with the gun barrel immediately in advance of the upper, thicker portions of said flange 17.

Under the force of the combustion and explosion gases wad 4 will also be subjected to a compression causing a temporary flattening thereof, which might normally develop into an undesirable buckling. However, with the present construction, ribs 22 eifectively resist any tendency toward buckling and exert a radially outwardly directed force against the outer portions of wad 4 so as to drive the upper portions of the side walls 13 thereof into sealing engagement with the gun barrel. Thus, it will be seen that a double sealing action is provided since ribs 22 serve to produce a sealing action by the upper portions of the side walls, while the lower portions are forced outwardly under the direct gas pressure operating against flange 17. In actual practice it has been found that the outer peripheral surface of wad 4 throughout its entire extent maintains sealing contact with the gun barrel so that actually a scrubbing action is developed.

Axial bore 16 formed in wad 4 is a novel feature not heretofore provided in'such wads, apparently through-the erroneous and ill-considered assumption that such might cause gas leakage. In effect, the limited amount of gas entering bore 16 will exercise an outwardly directed pres sure against the wall of said bore which will, thus, assist in urging ribs 22 radially outwardly. A seal will develop at the juncture of filler and bore 16, as indicated at X so that no gas leakage will eventuate. And thus by the present, novel construction, gas pressure is utilized internally of wad 4 for barrel-sealing purposes. It is to be particularly noted that the diameter of bore 16 is so relatively small that powder of charge 3- will not normally be received therein.

Furthermore, axial bore 16 serves to prevent the devel opment of undesirable air pockets with coincident pressure within the cartridge A as it permits gun wad 4 to be rammed tightly against powder charge 3 and with any displaced air being received within bore 16. This particular feature provides a marked advance over the prior art wherein the development of air pockets-has been considered as an accepted condition.

The obturating wad of the present invention develops what might be considered a wedging action within the gun barrel, and due to its unique structural features is designed to produce a snug and reliable seal. Furthermore, through its compressibility wad 4 will cushion the initial impact of the force of explosion and thereby exercise a damping action on transmission of the explosion to the shot mass. Furthermore, wad 4 is so compactly and durably constructed the same will not disintegrate under firing pressure, whereby the same conduces to a symmetrical shot pattern, providing shell A with excellent ballistic properties.

The use of gun wads 4 in shotgun cartridges has. conclusively proved that the same cause a marked increase in the breech pressure and shot velocity over cartridges having over-powder wads of the types heretofore known. In establishing such facts, the average breech pressure and shot velocity of 100 shots of cartridges embodying the present invention was compared with the correspondfined by a circular base wall 26 and an upwardly and outwardly' inclined, inner side wall 27. Radially ouh wardly of inner side wall 27 and concentric therewith is a peripheral flange 28 similar in construction to flange 17 described above with respect to gun wad 4 and, thus, embodies a wall 29 with an inwardly and upwardly inclined inner side face with a zone of increased flexibility 30 at its lower end, being spaced from the outer face of the side wall 27. Centrally of recess and extending i'ng averages for cartridges containing wads in current general use. In each shot a twelve (12) gauge shell was used with the only difference being the type of overpowder wad; thus the charge, shot, filler wads, and body were the same in each instance. The results of such shots may be set forth in the following manner:

Wad of .200 Plastic Paper Present inch H Type Cup Cup Ewen: Card- Plastic Wad Wad tion board Breech lgressure (Kilos per 7 s uare A'vera-ge 618 574 006 '674 687 Maximum Individual.-- 668 649 649 618 637 a Minimum Individual-.- 587 414 555 542 522 Shot Velocit; (Feet per saco'n'd) (Measured at 12 V feet from gun muzzle): 7

Average l, 223 1, 147 1, 178 '1, 169 1, 188 Maximum Individual". 1, 242 l, 176 l, 199 l, 185 1, 208 Minimum individual. l, 212 1, 108 1, 154 1,15 .1, 176

As a study of the foregoing table reveals, the cartridges equipped with obturating wads 4 have an average breech pressure and shot velocity substantially exceeding the related values for cartridges provided with any of the presently used over-powder wads. 7 Such determinations unequivocally indicate that the wads of the present invention effect a greater confinementof the charge than has been achieved by gun wads prior hereto.

Referring now to FIGURES 5 and 6 there is disclosed another form of gun or over-powder wad of the present invention indicated 24, which is of like, molded construction as wad 4 hereinabove-described and ofgeneral cylindrical character, incorporating a central, upwardly open ing, and upwardly and outwardly tapering'rece's'sis debe driven into gun-barrel sealing engagement.

upwardly from the base wall 26 is a hub or tubular portion 31 the upper end of which is planarwise parallel with the upper end of flange 28; there being an axial bore 32 extending through said hub 31 and bore wall 26.

Wad 24 will be disposed with respect to thepropellant' charge of a cartridge in'the same manner as wad 4 in that the bottom wall 26 will be in overlying relation to the charge, which latter will extend into the recess between flange 28 and inner side wall 27. The diameter of axial bore 32 is of'such limited character that powder will not normally enter same. Upon firing, flange 28 will be driven outwardly by the expanding gases into sealing engagement with the gun barrel, and with such gases entering bore 32 exerting an outwardly directed. force for countering any buckling tendency that might normally develop due to the compression of said wad 24 under the combustion and explosion forces. Further more, due to the outward inclination ofwall 27, the same will, acting under the force of the explosion, cause the upper portions of the outer side wall of wad 24 to- In the same manner as with gun wad 4, gas leakage willbe prevented due to the seal developed between gun-wad 24 and the immediately proximate filler wad 5 disposed thereabove. Thus, in all respects gun wad 24 acts effectively and reliably in providing an optimum seal.

It is to be particularly pointed out that in the drawings axial bores 16 and 32 of wads 4 and 24 respectively are not drawn to relative scale for purposes of illustration only. Actually said bores, having a diameter in the order of 1 millimeter, are considerably less in'diamettal extent than the cross section of the flange recesses of the respective wads, although such latter might appearto be comparable by perusal of the drawings.

It should be understood that changes and modifications in the formation, construction, arrangement,'and combination of the several parts of the obturating wad may be made and substituted for these'herein'shown and described without departing from the nature and principle of .my'invention.

Having thus described my invention, what I-claim -nnd desire to secure by Letters Patent is:

1. An obturating wad fora shotgun cartridge haying a propellant charge comprising a generally .cylindricalbody fabricated of moldable, compressible material having a -flat bottom wall'for confronting the propellant charge "axially perpendicular to the plane of said bottom wall,

a plurality of spaced apart ribs projecting outwardly from said tubular portion, said ribs being connected at their outer .ends to the inner face of said recess upstanding ,wall, and a peripheral flange provided spacedly outwardly of .said bottom wall, said body having a down wardly-opening, charge-confronting recess between flange. and said bottom wall.

'2. Anobturating'wadasdescribed in claimjl wherein said bottom wail is of circular configuration, said side "wall, flange and'downwardly opening recess are annular,

and said ribs extend radially from said tubular portion, said tubular portion being concentric with said upwardly opening recess.

3. An obturating wad in combination with a shotgun cartridge having a propellant charge, said wad comprising a generally cylindrical body fabricated of moldable, compressible material having a flat bottom wall for confronting the propellant charge and a side wall projecting therefrom in a direction remote from the propellant, said bottom wall and said side wall defining an upwardly opening annular recess having a lower portion and an upper portion, said lower portion being of reduced diameter relative to said upper portion, there being a tubular portion concentric with said recess and extending upwardly from said bottom wall, said tubular portion having an axial bore therethrough and through said bottom wall, and a plurality of ribs projecting radially from said tubular portion and being connected at their outer ends to the sides of the upper and lower portions of said recess. 7

4. An obturating wad in combination with a shotgun cartridge having a propellent charge, said wad comprising a generally cylindrical body fabricated of moldable, compressible material, having a bottom wall for confronting the propellant charge and a side wall projecting therefrom in a direction remote from the propellant, said bottom wall and said side wall defining an upwardly opening recess, there being a tubular portion centrally of said recess and extending upwardly from said bottom Wall, said tubular portion having an open-ended axial bore therethrough and through the bottom wall for connection with the portion of said cartridge containing the propellent charge, said bore being axially normal to the plane of the bottom wall, and a plurality of spacedapart rib members projecting outwardly from said tubular portion.

5. An obturating wad for a shotgun cartridge having a propellant charge comprising a generally cylindrical body fabricated of moldable, compressible material having a flat bottom wall for confronting the propellant 4o charge and a side wall projecting therefrom in a direction remote from the propellant charge, said bottom wall and said side wall defining an upwardly opening recess, there being a tubular portion centrally of said recess and extending upwardly from said bottom wall, said tubular portion having an open-ended axial bore therethrough and through the bottom wall for connection with the portion of said cartridge containing the propellant charge, said bore being axially perpendicular to the plane of said bottom wall, a peripheral flange provided spacedly outwardly of said bottom wall, said body having a downwardly-opening, charge-confronting recess between said flange and said bottom wall for reception of the charge therein, and a plurality of spaced apart rib members projecting outwardly from said tubular portion.

6. An obturating wad in combination with a shotgun cartridge having a propellant charge, said wad comprising a generally cylindrical body having an annular side wall and a transverse Wall, said latter confronting on one face the propellant charge, said body further having an upwardly opening recess defined by said transverse wall and the side wall portion remote from said propellant charge, a hub provided in said recess and extending upwardly from said transverse wall, and a plurality of rib members projecting radially outwardly from said hub and being connected at their outer ends to the adjacent portions of said side wall.

7. An obturating wad as defined in claim 6 wherein the ribs are of substantially the same height as the depth of the recess.

8. An obturating wad as defined in claim 6 and further characterized by said body being fabricated of moldable, compressible material.

9. An obturating wad as defined in claim 6 and further characterized by said hub-forming member being disposed centrally of said recess.

References Cited in the file of this patent UNITED STATES PATENTS 1,073,940 Sweeley Sept. 23, 1913 2,026,765 Woodford Jan. 7, 1936 FOREIGN PATENTS 531,477 France Feb. 21, 1921 767,412 France May 1, 1934 413,714 Italy May 21, 1946 532,481 Italy Aug. 23, 1955 1,153,958 France Oct. 21, 1957 

